UIAccessibilityAction

The UIAccessibilityAction informal protocol provides a way for accessibility elements to support specific actions, such as selecting values in a range or scrolling through information on the screen. For example, to respond to a scrolling gesture, you implement the accessibilityScroll: method and post UIAccessibilityPageScrolledNotification with the new page status (such as “Page 3 of 9”). Or, to make an element such as a slider or picker view accessible, you first need to characterize it by including the UIAccessibilityTraitAdjustable trait. Then, you must implement the accessibilityIncrement and accessibilityDecrement methods. When you do this, assistive technology users can adjust the element using gestures specific to the assistive technology.

Tells the element to activate itself and report the success or failure of the operation.

Declaration

Swift

funcaccessibilityActivate() -> Bool

Objective-C

- (BOOL)accessibilityActivate

Return Value

YEStrue if the element was activated or NOfalse if it was not.

Discussion

You can use this method to make complex controls more readily accessible to users. The accessibility system calls this method when a VoiceOver user double taps the selected element. Your implementation of this method should activate the element and perform whatever other tasks it deems appropriate. For example, you might use the method to activate a control that requires a complex gesture and would be difficult for VoiceOver users to perform, possibly because the gesture has a different meaning when VoiceOver is running.

After performing any tasks, return an appropriate Boolean value to indicate success or failure.

Import Statement

Availability

Tells the accessibility element to increment the value of its content.

Declaration

Swift

funcaccessibilityIncrement()

Objective-C

- (void)accessibilityIncrement

Discussion

If your element has the UIAccessibilityTraitAdjustable trait, you must implement this method. Use this method to increment the value of the element. For example, a UISlider object uses this method to increment its value by an appropriate amount.

Import Statement

Availability

Tells the accessibility element to decrement the value of its content.

Declaration

Swift

funcaccessibilityDecrement()

Objective-C

- (void)accessibilityDecrement

Discussion

If your element has the UIAccessibilityTraitAdjustable trait, you must implement this method. Use this method to decrement the value of the element. For example, a UISlider object uses this method to decrement its value by an appropriate amount.

Import Statement

Availability

Dismisses a modal view and returns the success or failure of the action.

Declaration

Swift

funcaccessibilityPerformEscape() -> Bool

Objective-C

- (BOOL)accessibilityPerformEscape

Return Value

YEStrue if the modal view is successfully dismissed; otherwise, NOfalse. By default, this method returns NOfalse.

Discussion

Implement this method on an element or containing view that can be revealed modally or in a hierarchy. When a VoiceOver user performs a dismiss action, this method dismisses the view. For example, you might implement this method for a popover in order to give users a deliberate dismiss action to perform that closes the popover.

Return Value

Discussion

The exact action performed by this method depends your app, typically toggling the most important state of the app. For example, in the Phone app it answers and ends phone calls, in the Music app it plays and pauses playback, in the Clock app it starts and stops a timer, and in the Camera app it takes a picture.

Declaration

Discussion

The array contains one or more UIAccessibilityCustomAction objects defining the supported actions. Assistive technologies such as VoiceOver display your custom actions to the user at appropriate times.